Semi-classical theory of collisional depolarization of spectral lines by atomic hydrogen I. Application to p states of neutral atoms

¹ Observatoire de Paris-Meudon, LERMA UMR CNRS 8112, 5 place Jules Janssen, 92195 Meudon Cedex, France
² Department of Astronomy and Space Physics, Uppsala University, Box 515, S 751 20 Uppsala, Sweden
³ Department of Physics, The University of Queensland, St Lucia 4072, Australia

Corresponding author: M. Derouich, Moncef.Derouich@obspm.fr

Received: 29 November 2002
Accepted: 4 April 2003

Abstract

The present paper extends the method of Anstee, Barklem and O'Mara (Anstee [CITE]; Anstee & O'Mara [CITE], [CITE]; Anstee et al. [CITE]; Barklem [CITE]; Barklem & O'Mara [CITE]; Barklem et al. [CITE]), developed during the 1990s for collisional line broadening by atomic hydrogen, to the depolarization of spectral lines of neutral atoms by collisions with atomic hydrogen. In the present paper, we will limit the calculations to p () atomic levels. The depolarization cross sections and depolarization rates are computed. In Table [see full text] cross sections as functions of the relative velocity and effective quantum number are given, allowing for the computation for any p atomic level. Our results are compared to quantum chemistry calculations where possible. The sensitivity of depolarization cross sections to regions of the potential is examined. We conclude that the accuracy obtained with our method (<20% for the depolarization rates) is promising for its extension to higher l-values for the interpretation of the “second solar spectrum”. This will be the object of further papers.